Java Object Oriented Programming

What is the process of hiding the details of an object in Java called?

• Abstraction
• Polymorphism
• Inheritance
• Encapsulation

Which keyword is used to create an object in Java?

• object

• new

• create

• instance

Which concept in Java is a mechanism where one class acquires the property of another class?

• Inheritance
• Polymorphism
• Encapsulation
• Abstraction

Which OOP concept allows an object to take on many forms?

• Encapsulation

• Polymorphism

• Abstraction

• Inheritance

Answer explanation

Polymorphism allows an object to take on many forms, enabling different classes to be treated as instances of a parent class.

Which OOP concept allows a class to be defined by its characteristics, such as fields, and its behavior, such as methods?

• Abstraction

• Inheritance

• Polymorphism

• Encapsulation

Answer explanation

Abstraction in OOP allows a class to be defined by its characteristics (fields) and behavior (methods), focusing on what an object can do rather than how it does it.

Which access modifier allows a class to be accessed from anywhere within the same package?

• protected

• private

• default

• public

Answer explanation

The 'default' access modifier allows a class to be accessed from anywhere within the same package, making it the correct choice in this scenario.

Which of the following is not a valid access modifier in Java?

• private

• protected

• global

• public

Answer explanation

The correct choice is 'global' because it is not a valid access modifier in Java. The valid access modifiers are private, protected, and public.

Only methods within the same class can access private members. (True/False)

• True

• False

Answer explanation

Private members can only be accessed by methods within the same class, making the statement true.

Which keyword is used to define a parent-child relationship between classes?

• parent

• derive

• super

• extend

Answer explanation

The keyword 'extend' is used to define a parent-child relationship between classes in programming languages like Java and Python.

What is the term used to refer to a variable that is shared by all instances of a class in Java?

• static variable

• shared variable

• common variable

• global variable

Answer explanation

A static variable is the term used to refer to a variable shared by all instances of a class in Java, making it the correct choice among the options provided.